SDLC - System Development Life Cycle

SDLC - System Development Life Cycle

Methodologies to Consider

The system development life cycle (SDLC) is the overall process of developing software using a series of defined steps. This section discusses several SDLC models that work well for developing applications in Oracle Application Express.

•             About Iterative vs. Planned Development

•             About the Advantages of Creating Prototypes

•             Waterfall

•             Spiral

•             Rapid Application Development

About Iterative vs. Planned Development

When developing applications using Application Builder, you must find a balance between two dramatically different development methodologies:

•             Iterative, rapid application development

•             Planned, linear style development

Iterative, rapid application development offers so much flexibility that you run the risk of never completing your project. In contrast, planned, linear style development can yield applications that do not meet the needs of end users even if they meet the stated requirements on paper.

About the Advantages of Creating Prototypes

The Oracle Application Express development environment enables developers to take a more iterative approach to development. Unlike many other development environments, creating prototypes is easy. With Oracle Application Express, developers can:

•             Use built-in wizards to quickly design an application user interface.

•             Make prototypes available to users and gather feedback.

•             Implement changes in real time, creating new prototypes instantly.

Methodologies that work well with Oracle Application Express include Spiral and Rapid Application Development (RAD).

SDLC models

Waterfall, fountain, spiral, build and fix, rapid prototyping, incremental, agile, and synchronize and stabilize. The oldest of these, and the best known, is the waterfall model: a sequence of stages in which the output of each stage becomes the input for the next.

Waterfall

The Waterfall is probably the best known SDLC model. In this methodology, the development process is broken down into the following stages:

1. Project Planning

                Establishes a high-level view of the intended project and determines its goals.

2. Requirements Definition

Defines project goals into defined functions and operation of the intended application. Analyzes end-user information needs.

3. Design

Describes desired features and operations in detail, including screen layouts, business rules, process diagrams, pseudo code and other documentation.

4. Development

                The real code is written here.

5. Integration and Testing

Brings all the pieces together into a special testing environment, then checks for errors, bugs and interoperability.

6. Installation and Acceptance

The final stage of initial development, where the software is put into production and runs actual business.

7. Maintenance

What happens during the rest of the software's life: changes, correction, additions, moves to a different computing platform and more. This, the least glamorous and perhaps most important step of all, goes on seemingly forever.

This methodology is referred to as a waterfall because the output from one stage is the input for the next stage. A primary problem with this approach is that it is assumed that all requirements can be established in advance. Unfortunately, requirements often change and evolve during the development process.

Spiral

A Spiral methodology is actually a series of short waterfall cycles. Each waterfall cycle yields new requirements and enables the development team to create a robust series of prototypes. One advantage of this approach is that it accommodates changing requirements. Disadvantages include complex project management and the risk development goes on indefinitely.

Rapid Application Development

A Rapid Application Development (RAD) methodology has a heavy emphasis on creating a prototype that closely resembles the final product. The prototype is an essential part of the requirements phase. Advantages of this model include the ability to accommodate changing requirements, rapid development cycles, and progress can be easily measured. The major disadvantage of this model is that the emphasis on prototyping can result in scope creep. As a result, developers can lose sight of their initial goals in the attempt to create the perfect application.